Casual carpooling, wherein strangers carpool with one another to and from job centers, could be viable in the North Bay, but it will take coordination from citizens and government to make it really take off.
When examining the modes of commuting, typically absent from the conversation is carpooling. Either it happens or it doesn’t, but governments and citizens will fixate on accommodating more traditional modes of transportation: single-occupant vehicles (SOVs, i.e., cars), buses, and trains, rather than actively trying to encourage carpooling.

There are a number of reasons for this, but I suspect a big one is that there is no ribbon to cut, no new lane or train to inaugurate. Another big one is the perception that carpooling only rests on social networks outside the reach of government intervention, where coworkers discover by happenstance that they live near enough to one another that carpooling becomes an option. Besides, interfering in carpooling takes attention away from the big capital projects that make headlines.

In spite of apathy from officialdom, the phenomenon of casual carpooling does arise in certain locales. Known in the Washington, DC, region as “slugging”, casual carpooling entails passengers forming lines at pickup areas, usually commuter lots or bus stops. A driver will approach the line, shout their destination (“Pentagon!” “Civic Center!”) and those bound for the area will hop in. It works both ways, and situating near bus stops gives passengers the option of a commuter bus if they’d prefer.

Casual carpooling gives drivers and passengers certain advantages over SOV driving. It allows them to use HOV lanes, saving time, and it allows passengers to save on driving costs such as gas and maintenance. For those who aren't in a carpool, carpooling means there's more for them: every passenger is one less car on the road and one less parking space taken. It’s a win for everyone. So why does it pop up in some locations but not others?

East Coastin’

The Washington, DC, region makes an interesting test case. Straddling as it does three states (DC, Maryland, and Virginia), we can see how different policies effect the outcome. Virginia has an active and large slugging community dating back to the 1970s, while Maryland’s community is relatively small. The principal difference, according to David LeBlanc, author of Slugging: The Commuting Alternative For Washington DC, is that Maryland uses HOV-2 lanes, where having only one passenger qualifies, while Virginia uses HOV-3 lanes, where two passengers are necessary to use the lane. He argues that HOV-3 lanes give passengers a sense of safety when getting into a car with a stranger, and spurs drivers to more actively pursuit warm bodies to fill their vehicles.

Dampers on casual carpooling include high-occupancy toll, or HOT, lanes, as Virginia will soon discover when its primary HOV corridor into DC is partially converted to HOT. If a driver can simply pay a toll to qualify, they will be less likely to detour to a slug line for passengers and clog the lanes with SOVs. The lack of HOV lanes, of course, will remove the incentive for the driver to pick up passengers as well.

North Bay Slugs

In other words, the North Bay, with its HOV-2 lanes that stop after Sausalito, is not ideally suited to casual carpooling. While Northern Virginia has an entire reversible highway dedicated to HOV-3 that extend all the way from suburbs to job centers in Arlington and the District, complete with their own exits and with limited access, the North Bay has only a single HOV lane in either direction that requires drivers to slow from top speed to the speed of traffic in order to merge over to the exit, and which stops before reaching either the East Bay or San Francisco. Although it’s conceivable that a small, Maryland-style community could spring up in the North Bay with the right tools – an app, say, allowing potential carpoolers to mark off their home and destination – true casual carpooling will require a bit more intervention at the governmental level. As with everything, there are cheap and expensive solutions.

On the cheap side, just switching our HOV lanes to HOV-3 would be a boon, giving drivers a greater incentive to pick people up. Following up the switch with congestion pricing on both bridges applicable only to SOVs would prove a high-profile shot in the arm for any casual carpooling system. Given the hubbub over the last attempt to institute congestion pricing on the Golden Gate Bridge, the press would be wonderful. Instituting a peak-only HOV lane on the southbound side of the bridge would be another major reward for carpoolers: no more waiting in line at the toll plaza. Instituting congestion pricing at the Sonoma/Marin border or just north of Marinwood* would stimulate casual carpooling among Sonomans coming to Marin – our largest in-commuting population – and would raise millions for transit projects between the two counties.

On the expensive side, CalTrans might consider combining Highway 101’s two carpool lanes into a single, reversible HOV freeway, complete with limited access and dedicated on/off ramps. This would make carpooling significantly safer and faster, and would have the added bonus of improving bus access along the freeway. The cost, however, would likely be upwards of $1 billion given the technical challenges of HOV exits and the cost so far just to extend regular HOV lanes.

It has been suggested that the app described above would help drive a casual carpooling renaissance, but the truth is that these networks typically form in response to everyday commute pressures - heavy traffic, centralized job centers - that ultimately come from structures either put in place by government or arising out of commuting physics. That’s not to say technology does not have a role to play – casual carpool networks often have websites to guide potential participants and there are a number of apps already in existence – but a truly robust system will be one that arises organically. Drivers will only take the time to pick up passengers when they can clearly see that it is worth their time or money to do so.

Casual carpooling in Virginia has been described as another transit system by the Virginia Department of Transportation, complementary to the existing Metrorail and bus systems. It certainly has a place in the highway-centered transportation systems of the US, but it will take work to implement in the North Bay.

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*Most freeway traffic in Marin actually comes from Novato, not from Sonoma; although instituting congestion pricing there would be a political nonstarter, it would make the most sense from a practical standpoint.

For information on casual carpooling in the Bay Area, RideNow.org has a website dedicated to the local network. For information on ridesharing in the Bay Area, you might want to look into eRideshare.com. For information on how the slugging system works in Virginia, local NPR affiliate WAMU aired an hour-long segment on the subject, while local transit blog Greater Greater Washingtonhas a number of posts on the subject.